fix(dev build): reserving unused port vuejs#26

Author: FadySamirSadek

lib/dev.js

@@ -10,6 +10,7 @@ module.exports = async function dev (sourceDir, cliOptions = {}) {
   const serveStatic = require('koa-static')
   const HTMLPlugin = require('html-webpack-plugin')
   const history = require('connect-history-api-fallback')
+  const portfinder = require('portfinder')
 
   const prepare = require('./prepare')
   const HeadPlugin = require('./webpack/HeadPlugin')
@@ -71,7 +72,12 @@ module.exports = async function dev (sourceDir, cliOptions = {}) {
   }
 
   const compiler = webpack(config)
-  const port = cliOptions.port || options.siteConfig.port || 8080
+  portfinder.basePort = cliOptions.port || options.siteConfig.port || 8080
+  const port = await portfinder.getPortPromise()
+    .then((port) => {
+      return port
+    })
+    .catch(err => console.log(err))
 
   let isFirst = true
   compiler.hooks.done.tap('vuepress', () => {

package.json

@@ -69,6 +69,7 @@
     "nprogress": "^0.2.0",
     "object-assign": "^4.1.1",
     "optimize-css-assets-webpack-plugin": "^4.0.0",
+    "portfinder": "^1.0.13",
     "postcss-loader": "^2.1.3",
     "prismjs": "^1.13.0",
     "register-service-worker": "^1.2.0",